docs: def _get_bib_element(bibitem, element):
      """Return element from bibitem or None.
  
      Paramteters
      -----------
      bibitem :
      element :
  
      Returns
      -------
  
      """
      lst = [i.strip() for i in bibitem.split("\n")]
      for i in lst:
          if i.startswith(element):
              value = i.split("=", 1)[-1]
              value = value.strip()
              while value.endswith(','):
                  value = value[:-1]
              while value.startswith('{') or value.startswith('"'):
                  value = value[1:-1]
              return value
      return None